<!DOCTYPE html>
<html lang="en">

<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
	<style>
		.box {
			background: sandybrown;
			width: 500px;
			height: 300px;
			padding-right: 100px;
			position: relative;
		}

		.inner {
			width: 50%;
			height: 50%;
			padding-left: 50%;
			background: olivedrab;
		}

		.son {
			width: 50%;
			height: 50%;
			background: firebrick;
		}
	</style>
</head>

<body>
	<div class="box">
		<div class="inner">
			<div class="son"></div>
		</div>
	</div>
</body>

</html>